i have a switchable ballast and reflector, but i was reading other posts of people saying it was fine to put in a lower watt bulb in a higher watt ballast, the only thing was that it would burn out more quickly. i know, i can't set up an inline (i'm renting a house) so i have a couple of fans going all the time. i was using CFL'S but i wanted to bump it up a bit. plus the fans are way too expensive and i've already done about $800 not including seeds and the other odds and ends you find you need along the way.